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 A182402 Total number of digits in n-th row of a triangle formed by the positive integers. 2
 1, 2, 3, 5, 10, 12, 14, 16, 18, 20, 22, 24, 26, 34, 45, 48, 51, 54, 57, 60, 63, 66, 69, 72, 75, 78, 81, 84, 87, 90, 93, 96, 99, 102, 105, 108, 111, 114, 117, 120, 123, 126, 129, 132, 171, 184, 188, 192, 196, 200, 204, 208, 212, 216, 220, 224, 228, 232 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Sequence is nonlinear at each decade transition; for example, row-5 transitions from single-digit (7) to double-digit (10) where sequence jumps (3) to (5); row-14 transitions from 2-digit (92) to 3-digit (105) where sequence jumps from (26) to (34). The rows of nonlinearity are given by A068092. - Jon Perry, May 26 2013 LINKS Reinhard Zumkeller, Table of n, a(n) for n = 1..10000 FORMULA a(n) = A058183(A000217(n)) - A058183(A000217(n-1)), n >= 2. - Omar E. Pol, Jun 25 2012 EXAMPLE 1; .................... (row 1 contains 1 digit) 2,   3; ............... (row 2 contains 2 digits) 4,   5,  6; ........... (row 3 contains 3 digits) 7,   8,  9, 10; ....... (row 4 contains 5 digits) 11, 12, 13, 14, 15; ... (row 5 contains 10 digits) MATHEMATICA f[n_] := Length@ Flatten[ IntegerDigits[ Range[n (n - 1)/2 + 1, n (n + 1)/2]]]; Array[f, 58] (* Robert G. Wilson v, Sep 04 2013 *) PROG (Haskell) a182402 n = a182402_list !! (n-1) a182402_list = map (sum . map a055642) \$ t 1 [1..] where    t i xs = ys : t (i + 1) zs where      (ys, zs) = splitAt i xs -- Reinhard Zumkeller, May 26 2013 CROSSREFS Cf. A055642, A226029 (first differences). Cf. A068092. Sequence in context: A002263 A249991 A039022 * A079251 A171785 A050051 Adjacent sequences:  A182399 A182400 A182401 * A182403 A182404 A182405 KEYWORD nonn,base AUTHOR Dave Durgin, Jun 19 2012 EXTENSIONS Better definition from Omar E. Pol, Jun 25 2012 STATUS approved

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Last modified May 13 05:02 EDT 2021. Contains 343836 sequences. (Running on oeis4.)